GILBERT, Ariz. (AP) — Many considered Jason Todd Ready to be the most high-profile neo-Nazi in Arizona. He led groups of heavily armed civilians into the desert to look for illegal immigrants as he repeatedly tried to win public office.

But Ready’s beliefs and actions got so extreme, including statements that land mines would be a good way to stop border crossers, that the state’s most conservative politicians distanced themselves from him.

Unwelcome among Republicans, Ready ran for sheriff in January as a Democrat. He continued to lead immigration patrols and posted Facebook updates, but there was little to suggest his personal life was in turmoil.

On Wednesday, police said, Ready, a burly 39-year-old who went by “JT,” shot and killed four people, including a 16-month-old girl, in the Phoenix suburb of Gilbert where he lived. He then turned the gun on himself.

The dead included Lisa Lynn Mederos, 47, who was Ready’s girlfriend; her daughter Amber Nieve Mederos, 23; and Amber’s boyfriend, Jim Franklin Hiott, 24. The child was found alive but was pronounced dead at a hospital.

Gilbert police Sgt. Bill Balafas said a woman believed to be Lisa Mederos called 911 around 1 p.m. Wednesday asking for the police to come to the house. Not long after, the operator heard shots fired and the line went dead.

Shortly after that, a teenager in the house who heard arguing followed by gunshots found the bodies and called 911 on a separate line.

Balafas said all the evidence suggests a domestic dispute but investigators aren’t sure what triggered it.

He said Gilbert police have gone to the Mederos home five times since 2009, most recently in February, when Lisa Mederos called to report that Ready had choked her in August 2011.

Balafas said there was not enough evidence to make an arrest, and no charges were filed. It was unclear why Mederos would have waited six months to make the call.

The other times police responded to the home included a suicide threat by Amber Mederos in November 2009 and a suspicious activity report filed by Ready, Balafas said.

The killings and Ready’s involvement stunned members of his group, the U.S. Border Guard.

“Our sympathies go out to all of his family and friends during this time of unbelievable grief and pain,” according to a statement posted on its website. “God bless you, J.T. You will be fiercely missed.”

Harry Hughes, a regional director for the National Socialist Movement who went out on patrols with Ready, said the shooting was “completely out of character” for Ready.

“And I’m going to not speculate or make any conclusions. I’m going to let the investigation go take its course,” Hughes said. “But I have a real hard time believing that JT Ready could actually shoot and kill a child.”

Anti-hate groups such as the Southern Poverty Law Center have for years tracked Ready. “JT Ready was a violent thug who typifies the very worst element in the American nativist movement,” said the SPLC’s Mark Potok.

According to an SPLC profile on its website, Ready was court-martialed twice in 1996 while serving in the U.S. Marine Corps, the first time after being gone for eight days without permission.

The center said Ready was demoted to private after the absence and jailed for three months, and then later that year was court-martialed again for conspiracy, assault and wrongful solicitation and advice. He was found guilty, spent six months in detention and was discharged for bad conduct, the center said.

The Marine Corps was trying to confirm the center’s information.

Ready’s ex-wife, Arline Lindgren, knew that he had started associating with white supremacist groups when they were married in the late 1990s, said her brother, Adam Lindgren. The couple divorced in 2003.

Lindgren said he got into a few arguments with Ready but they were never violent. He said Ready had a temper, but “not a violent temper, that I was aware of.” He said he never saw Ready be violent toward anybody.

Ready was “very, very opinionated. He would argue with you until ... well, just keep arguing with you,” he said.

Ready was a member of the Detroit-based National Socialist Movement, whose members promote white separatism, dress like Nazis and display swastikas. It believes only non-Jewish, white heterosexuals should be American citizens and that everyone who isn’t white should leave the country “peacefully or by force.”

Ready first tried to get into politics in 2004, when he unsuccessfully ran for a seat in the Arizona House. In 2006, he lost a run for Mesa City Council but was later elected as a Republican precinct committeeman.

He didn’t run for re-election in 2008 after three Republican congressmen wrote a letter to a GOP county chairman asking for his removal because of his neo-Nazi ties. They said Ready was sullying the party’s image. They said he was a featured speaker at a neo-Nazi conference in Omaha, Neb., in September 2007 and distributed racist and anti-Semitic literature at a GOP meeting.

Trying to distance himself from the movement, Ready told The Arizona Republic in 2010 that he left the group. Potok said the move was “merely for cosmetic reasons.”

Ready was also running his desert operations targeting illegal immigrants, one of which was featured on the National Socialist Movement’s website as recently as January. Some of the photos on the website match ones posted to his Facebook page.

They include images of Ready and other members wearing head-to-toe camouflage gear, helmets and boots, and carrying high-powered guns during a weekend operation ending Jan. 29. The group claimed to help the U.S. Border Patrol apprehend one illegal immigrant.

“Some of us have our fingers on the triggers,” Ready wrote in a post on a website for his group. “Soap box. Ballot Box. Ammo box. These were given to us by our founding fathers and mothers. We have just about depleted the first two options.”

Police found six military-issue 40 mm grenades inside the Mederos home, U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives agent Tom Mangan said Thursday. The grenades require a launcher, and Mangan said authorities did not find one.

Hughes defended Ready’s desert operations, saying the primary focus of his group was to find and report drug smuggling.

“And from time to time, we would find human smuggling. We would find stranded motorists. We would find illegal aliens that were stuck out in the desert without water,” he said. “We actually saved about two dozen lives out there the last two years — people who would be dead today if we hadn’t come across them,” he said.

In January, Ready announced that he wanted to become sheriff in Pinal County, a sprawling area southeast of Phoenix that includes large swaths of desert that serve as a corridor for human and drug smugglers. Ready listed himself as a Democrat in his paperwork, and most considered his chances of being elected laughable. They speculated that he wanted some media attention.

At the time, Joe Robison, chair of the Pinal County Democrats, said Ready was too much of an extremist to get elected. “I don’t think there’s a snowball’s chance in hell of getting him elected,” Robison said.

Former Arizona Rep. Russell Pearce, the chief architect of some of the state’s tough legislation against illegal immigrants, was once Ready’s political ally and friend, but said in a statement that he distanced himself after learning of Ready’s ties to white supremacists.